This is the louche world of the posh swinger’s party. A secretive sex fest that each summer sees some of Britain’s most beautiful homes play host to a series of exquisite orgies.

These parties are strictly by invitation only and not for the faint-hearted — or the less than beautiful.

Yet The Sun gained exclusive access to one exclusive event to lift the lid on what goes on behind the gates of the privileged.

Sarah and Jim, pictured, attended a party at a swish manor house in Surrey, paid for by a mystery rich backer, after being invited by friends

MOST READ IN LIVING

Tying the knot

The lowdown on the differences between marriage and civil partnerships

warning signs

Seemingly normal aches and pains in your legs could be a sign of serious DVT

Snore off!

Another sleepless night? Steps to stop your partner snoring once and for all

INCURABLE CONDITION

What is cystic fibrosis? The causes, diagnosis and treatment

FAMILY UNIT

Meet Vicky Karayiannis, wife of Chris Cornell who died after committing suicide

SANDY'S GIRL

How Chloe Lattanzi overcame addiction to support mum Olivia Newton-John

Only the best looking and most adventurous swingers make the grade and the guest list includes household names from showbiz, TV and sport.

The rules are strict, mobile phones have to be left at the door and no celebrity names are ever to be revealed. Only official photographs are taken, with masks firmly in place.

With themes such as The Beautiful And The Damned and entry costs up to £2,000, they are a magnet for celebrities.

Premier League footballers, actors, singers and TV presenters lose their inhibitions, safe in the knowledge everyone present has to keep silent or never be invited again

Premier League footballers, actors, singers and TV presenters lose their inhibitions, safe in the knowledge everyone present has to keep silent or never be invited again.

In 2013 one posh location of a high-class swingers’ party was revealed to be 15-bedroom Rockwood Estate near Guildford, Surrey — the former home of ex-Pakistan PM Benazir Bhutto.

And Halswell House, in Somerset, was the scene of a masked ball which reportedly descended into an orgy in 2009.

Our guides are seasoned swingers Sarah Turner, 24, who works for a digital marketing agency, and her long-term partner Jim Wiseman, 23, who has a job in the building trade.

SWNS - BRISTOL

Premier League footballers, actors, singers and TV presenters lose their inhibitions, safe in the knowledge everyone present has to keep silent or never be invited again

SWNS:South West News Service

In 2013 one posh location of a high-class swingers’ party was revealed to be 15-bedroom Rockwood Estate near Guildford, Surrey — the former home of ex-Pakistan PM Benazir Bhutto

SWNS

Halswell House, in Somerset, was the scene of a masked ball which reportedly descended into an orgy in 2009

The couple, from Didsbury, Gtr Manchester, attended a party at a swish manor house in Surrey, paid for by a mystery rich backer, after being invited by friends.

Sarah says: “Standing in the hot summer night in early June, my hands nervously clasped around the stem of a champagne glass, I tried not to stare as a dignified grey-haired man reached out to a beautiful supermodel.

“There was a feeling of tension, a sense of excitement that anything could happen.

'Various scenarios were taking place, men having sex with women while pleasuring another woman, women making love to each other while a man watched'

“I wore a long, black silk dress, with a slit up the side, and expensive La Perla lingerie I bought specially.

“Jim was in a tuxedo. I tried not to gawp as we swept in through the gates of a stunning manor house.

“We’d been invited by friends and were so flattered we had been judged beautiful enough to attend.

“As soon as we were in the grounds it became clear how exclusive this party was.

“Jim whispered, ‘That’s a Premier League footballer over there’.

“I looked over to see a well-built man in black tie standing with his wife looking as if they were at an upmarket cocktail party.

SWNS - BRISTOL

Tickets to the invitation-only masked orgies cost £2,000

SWNS - BRISTOL

'There were threesomes, foursomes, bondage, girl on girl ... you name it'

“The chat was like any party. We talked about the weather, holidays we’d been on, even Brexit.

“But all of us knew this was no ordinary party. The costumes were a giveaway. There was lots of lacy lingerie and sexy, almost bondage wear, such as corsets and fetish black bras and knickers.

“Then people started to disappear, peeling off in twos and threes . . .

“The signal that people ‘wanted’ you inside was very subtle, a hand on the back, taking your hand or leaning in for a kiss on the cheek and a whispered invitation.

“No one gives their name though, you didn’t ask who people were.

“Jim and I wandered inside giddy with excitement to be met by a scene that he described as ‘like a painting of an orgy’.

“Some people were naked, some were still in their underwear, most were having sex or watching.”

Jim adds: “There was nothing so crude as couples having sex in the upright position in the corridor.

“Rather, sex took place on the cushions and the futons artfully placed around the living room.

“Various scenarios were taking place, men having sex with women while pleasuring another woman, women making love to each other while a man watched.

“Virtually every scenario took place, without any inhibition.

“One woman was spread-eagled on the floor while two men made love to her at the same time.

“There was a lot of girl on girl action, group sex, threesomes, foursomes, you name it.

“One woman was perched on a chair wiggling her bum about as she pleasured two masked men.

“Another blindfolded man who still had his tuxedo jacket on was being led into a side room by three women wearing nothing but strategically-placed feathers.

“Some couples or groups were more discreet and made love with covers over them, but there was no shame or embarrassment. It felt very natural and good-natured.”

Sarah continues: “In the huge, beautifully decorated rooms were bowls of condoms. We were told everyone had to have safe sex.

Getty Images

One woman was spread-eagled on the floor while two men made love to her at the same time

“Jim and I found it very arousing and we began kissing and fondling each other.

“I knew he found some of the women really sexy and his eyes were all over the place. We turned each other on by asking who we’d like to sleep with and what we’d like to do with them.

“There’s no jealousy, we trust each other. Parties are about sexual tastes and eroticism.

“We got incredibly turned on and we did indulge.

“Most people there were with partners, only couples and single women are invited.

“There are lots of people who get turned on watching their partner have sex with someone else, or a group of other people.

“I was amazed so many well-known people were prepared to take such a risk. There were famous footballers and actors with their wives and partners, captains of industry, TV presenters. It was obvious they do this often as they were so relaxed.

SWNS - BRISTOL

Only the best looking and most adventurous swingers make the grade and the guest list includes household names from showbiz, TV and sport

“There were no rules or boundaries beyond not putting anyone under any pressure.

“We were curious to see the guy who was hosting the party though we were never introduced to him. I was told he loves swinging.”

Jim says: “The organisers of these parties make it very clear no one must be coerced into sex or made to do anything they don’t want.

“Afterwards people would get up, slip on some clothing, then go to rejoin the party or select a different partner or partners.

“Sarah and I had a ball and we’re hoping to attend more events.

“But I certainly learned wealthy and famous people really know how to swing.”

HOT LIST: TOP RISQUE CLUBS

HERE is our guide to the UK’s poshest sex parties:Killing Kittens: Launched by Emma Sayle, a former school pal of Kate Middleton. Held from London to New York.Fever Parties: Mainly in London’s West End. Entry is by sending a sexy photo of yourself.The Skirt Club: For “girls who want to play with girls” at many different venues. Guests asked to “dress tastefully”.Shushi Parties: All over UK for “sexually confident” under-40s.